Machine tool structure and control mechanism



"Max 6, 9 1- J. B. ARMlTAGE ,2 7

MACHINE TOOL STRUCTURE AND CONTROL MECHANISM Filed June 5, 1957 '7Sheets-Sheet 1 .9 INVENTOR I Jaw/w fi. AFN/774G155 7M MW v ((44;

64 ATTORNEY May 6, 1941. J. B. ARMITAGE MACHINE TOOL STRUCTURE ANDCONTROL MECHANISM Filed Jime S 1937 7 Sheets-Sheet 3 INVENTOR 17/- M255)[3. Alr/wmaz A'IZTORNEY May 6, 1941. J. B. ARMITAGE 2,240,973

' MACHINE TCOL STRUCTURE AND CONTROL MECHANISM FiIed June 5, 19:57 7Sheets-Sheet 4 INVENTOR fisE/ HB. ARM/77105 ATTORNEY y 1941' Y J. B.RMITAGE 2,240,973

MACHINE TOOL STRUCTURE AND CONTROL MECHANISM Filed June 5, 1937 '7Sheets-Sheet 5 V INVENTOR JasfP/v 5. Afiw/ TA a5 ATTORNEY May 6, 1941.J. B. ARMITAGE MACHINE TOOL STRUCTURE AND CONTROL MECHANISM Filed June5, .1957 7 Sheets-Sheet 6 INVENTOR J0sPH 5. ARM) TA GE BY 77 w WWI/V]ATTORN EY I May 6, 1941, J. B. ARMITAGE MACHINE TOOL STRUCTURE ANDCONTROL MECHANISM Filed June 5, 1937 7 Sheets-Sheet 7 QQ MNN WNW MNINVENTOR JZJfPH Z3. A/P/V/ T405 BY W [a ATTORNEY Patented May 6, 1941UNITED STATE s PATENT OFFICE MACHINE TOOL s'mUc MECHANI Joseph B.Armitage,

to Kearney & Trecker TUBE AND CONTROL Wauwatosa, Wis., assignorCorporation, West Allis,

This invention relates generally to improvements in machine tools andmore particularly to improved operating mechanism and spee'd controllingapparatus for a milling machine.

A general object of .theinvention is to provide improvements in theconstruction of a milling machine power transmission and controlmechanism of character resulting in greater convenience in operatingthemachine, and in reducing the risk of damage occurring while adjustingthe moving parts of the machine.

Another object of the invention is to provide improved mechanism forcontrolling the shifting of speed changing gearing in a machine tool orthe like.

' Another object is to provide a transmission mechanism havingmechanically actuated and hydraulically actuated gear shifting apparatusarranged to function cooperatively to effect speed adjusting gearchanging movements of the mechanism.

Another object is to provide a speed changing transmission mechanismhaving two speed changing devices arranged in series relationship and asingle control device arranged to directly shift one speed-changingdevice and to indirectly shift the other speed-changing device bypre-selecting a subsequently effected shifting movement there- Anotherobject is to provide a speed-changing transmission mechanism having asingle speedselecting member associated with means operativepre-requisite to a speed-selecting movement of the member to render partof the speed-changing mechanism non-responsive to the speed-selectingmovement, and means operative subsequent to a speed-selecting movementof the member to effect response of the previously non-responsive partlationship and arranged to be driven by a of the mechanism in accordancewith an adjust- K ment preselected by the ,speed-selecting movement ofthe member.

Another object is to provide a machine tool 7 speed-changingtransmission mechanism including a variable speed device and arangechanger both adjustable in response to movement of aspeed-selecting member, together with means arranged to preventadjustment of the range changer until adjustment of the variable speeddevice has been completed.

' Another object is to provide an auxiliary'drive mechani'sm of improvedconstruction for slowly rotating the gears of a speed-:cha gingapparatus 0 facilitate thewhile they are being shifted, shiftingoperation.

Another object is to provide an auxiliary drive trol apparatus of thedriving motor of a machine tool.

According to this invention, a machine tool such as a milling machine isprovided with an improved speed-changing apparatus, including a variablespeed device and a range changing device, the two devices beingdisconnecting clutch disposed to transmit power to one of them. Aspeed-selecting member is arranged to shift the gears of the variablespeed device directly, and to pre-select an adjustment of the gears ofthe range changerfor subsequent shifting by power. As a pre-requisite toa speedselecting movement, a latch on the speed-select ing member isarranged to function, upon unlatching movement thereof, to disengage themain clutch and to engage an auxiliary slow speed drivingmechanism toreduce the speed of rotation of the gearing for facilitating shifting ofthe variable speed device. The unlatching movement also acts toestablish a condition preventing shifting of the range changer duringthe shifting of the variable speed device. After the variable speeddevice has, been shifted, latching movement of the latch on thespeed-selecting member disconnects the slow speed driving device andfunctions to permit shifting of the range changer by power in accordancewith the preselected adjustment. The auxiliary slow speed drivingmechanism is of improved construction, and the machine is provided withan improved control arrangement for actuating the starting clutch andfor starting and stopping the driving motor.

The foregoing and other objects of the invention, which will become morefully apparent from the following detailed description of apparatusexemplifying the invention, may be achieved by the millingmachinedescribed'herein as a preferred embodiment thereof in connection withthe accompanying drawings, in which:

Figure 1 is a view in left side elevation of a milling machine of theknee and column type embodying the principles of this invention.

Fig. 2 is a view in vertical cross section of the upper part of themilling machine taken on looking from the front of the machine.

Fig. 3 is a view in vertical longitudinal section connected in seriesrethe planes represented by the line- 2-2 in Fig 1;

of the upper part of the milling machine taken on the planes representedby the line 3-3 in Fig. 2, looking from the left side of the machine.

Fig. 4 is an enlarged detail view in vertical.

plane represented by the line 6-6 in Fig. 5, the

fixed valve ports being indicated by dotted circles. Fig. 7 is adetailview similar to Fig. 6 but position.

Fig. 8 is a 'detail view of one side of the second showing the valveturned'to its other operating I ary gear shifting. cam, taken partly insection on the plane represented by the line 8-'-8 in Fig. 5.

Fig. 9 is a view of the opposite side of the cam shown in Fig. 8, takenpartly in section on the plane represented by the line 9-9 in Fig. 5.

Fig. 10 is a detaihview of the primary gear shifting cam and part of thedriving mechanism,

taken partly in section on the plane represented by the line Ill-l0 inFig. 5.

Fig. 11 isa detail view of the range changing valve controlling cam,taken partly in section on the plane represented by the line lll l inFig. 5.

Fig. 12 is a detail'view of the shifting mechanism associated with thesecondary'cam, taken partly in section on the plane represented by theline l2l2 in Fig. 5, the follower engaging the opposite side of the cambeing shown in dotted lines.

Fig. 13 is a plan view, partly in horizontal section, of the secondarygear shifting mechanism, taken on the plane represented by the lineI3-l3 in Fig. 12.

Fig. 14 is a schematic diagram of the hydraulic control circuit foreffecting shifting of thespeed changing gear mechanism, the slow speedauxiliary drive and other associated mechanisms being shown inlongitudinal vertical section.

Fig. 15 (sheet his a detail view in transverse vertical section of partof the slow speed auxiliary drive mechanism taken on the planerepresented by the line Ii-liin Fig. 14,.and

Fig. 16 is another. detail view of the auxilia drive mchanism taken intransverse vertical section on the plane represented by the line ,lS-IGin Fig. 14, looking in the direction opposite to that in which themechanism is viewed in Fig. 15.

Referring more particularlyv to the drawings, the machine shown thereinas an example of apparatus constituting a preferred embodiment -'of theinvention, is a milling machine of the horizontal spindle, knee andcolumn type. As shown in Fig. 1, they milling machine comprisesessentially an upstanding 'column 20 mounted on a forwardly projectingbase 2|, preferably formed integrally with the, column and consti--tuting with it the supporting frame of the machine. Near the top of thecolumn there is journaled the usual horizontally disposed toolsupporting spindle 22, and above it are slidably mounted overarms 23 forsupporting a cutter arbor in well known-manner.

The tool spindle 22, and other parts of the machine, are preferablydriven by'meahs of an electric motor (not'shown) that is mounted his.

motor compartment 24 formed within and extending transversely of thelower part of the column 20. Starting or stopping of thespindle 22 isaccomplished by actuating a clutch lever or starting lever 25 mounted onthe top of the column and that carries a built-in push button switch 26for starting or stopping the motor in the compartment 24. The speed atwhich the spindle 22 is operated may be adjusted by means of aspeed-selecting lever or crank 30 that functions to shift speed-changinggearing mounted in a gear compartment 3| within the column 29 directlyabove but separated from the m tor compartment 24, the spindle speedbeing ndicated by a speed indicating dial 32.

For supporting a workpiece in cooperating relationship with a cuttingtool mounted in the tool spindle 22, there is provided a longitudinallymovable work supporting table 35 mounted on a transversely movablesaddle 36 that is in turn carried by a vertically movable knee 3'!slidably mounted on a vertically disposed bearing surface 39constituting the front face of the column 20.

To prevent chips or other foreign material from entering between thebearing face 38 on the column and the complementary bearing surface ofthe knee 31, there is provided a bearing wiper or chip guard 4|, shownin Figs. 1, 3, and 4, which is carried by the knee in position to engagethe face38 of the column just above the top of the knee bearing surface.As shown in the enlarged sectional view, Fig. 4, the bearing guard 4|comprises a wiping member 42 extending across the column face 38 andprovided with an upwardly and rearwardly projecting lip 43 arranged toclosely engage and scrape the column face 38 as the knee 31 is movedupwardly. To retain the wiping strip 42 in position, there are provideda plurality of retaining screws 44 passing loosely through spaced slots45 in the wiping strip and threaded into the top of the knee bearingstructure. The slots 45 permit limited movement of the wiping strip 42relative to the knee toward or from the bearing face 38; and the stripis frictionally retained in position by means of light spring washers 46interposed between the heads of the screws 44 and the top of the strip42.

For urging the'lip 43 of the wiping strip 42 into close engagement withthe face 38 of the column, there is provided a flat spring member 41which bears against the exposed forward edge of the strip 42 and issecured to the knee by screws 48 in manner to exert a continuous forceupon the strip 42 of suificient magnitude to overcome the frictionalrestraining action of the spring washers 46. By this arrangement, thescraping lip 43 of the wiping strip is maintained in close'engagementwith the bearing surface 38 regardless of changes resulting from slightwear of the strip or of the bearings. Anychips or other foreignmatterwhich may be thrown against the face of the column are scraped offby the scraping lip 43 as the knee moves upward and are prevented fromentering between the bearing surfaces.-

Horizontal bearing surfaces 49 on the top of the knee 31, upon which thesaddle 36 moves toward or from the column, may likewise be provided withchip guards of similar nature. As a further protection to .the bearingsurfaces 49, provision is made forthe disposal oichips or the like whichaccumulate on top of the knee. As shown in Figs; 1 and 3, a chipdisposal passageway 59 is formed in and extends downward through theknee, in manner mor ully described and claimed in Patent: No. 1,685,920,ued 'October 2, 1928 to 2,240,973 Edward J. Kearney and entitled.Maohine tool over a clutch pulley 56. The pulley 56 is provided with aninwardly extending hub or sleeve 51 which projects through and isrotatably supported in a bracket 58 mounted in the right side of thecolumn 28. The pulley hub or sleeve 51 is pro- 'vided at its inner endwithin the gear compart ment 3| of the column 28, with a gear wheel 59which meshes with an idler gear wheel 68 constituting part of. thegeartr'ain provided fornroying the work supporting members at-rapi djtraverse rate and arranged to operate continuously whenever the drivingmotor is operating; The idler gear 68 also drives a gear pump 6| mountedin the bracket 58 that furnishes oil under pressure for lubricating theworking parts within the column of the machine and for actuatinghydraulic control mechanism, as more fully explained hereinafter irfconnection with Fig. 14.

Within the hub 51 of the pulley 56,'there is rotatably mounted a hollow.main driving shaft 62 formed in two'parts for convenience in assemblingthe machine, and which may be selectively connected to be driven by. thepulley by means of a friction clutch 63. For actuating the clutch 63,there is provided a longitudinally movable clutch shifting rod 64 whichextends through the hollow shaft 62 and is provided at its outer endwith'a clutch cone 65 which, when moved to the right as shown in Fig.2-, acts upon clutch engaging fingers 66 to engage the clutch 63 fordriving the shaft 62. At its inner end, the clutch shifting rod 64 isconnected by means-of a pin 61, working in a slot in the inner part ofthe hollow shaft 62,

with a clutch shifting spool 68 which is slidably mounted on the shaftand is engaged by a shifting yoke 69. The shifting spool 68 is providedwith a brake cone 18'disposed to engage a stationary braking surface1lin the column structure, the arrangement being such that when theshifting spool 68 is moved to the left to central position by theshifting yoke 69, the clutch 63 is disengaged to disconnect the drivingpulley 56, andupon further movement to the left, the brake cone18 may beengagedwith the braking surface 1| to stop rotation of the main shaft 62and the mechanism driven from it. D

As shown, the clutch shifting yoke 69 is carried on one end of ashifting rack bar 12 having rack teeth that are engaged by a pinion 13mounted on the lower end of a hollow vertically disposed clutchoperating shaft 14. The clutch operating shaft 14 extends upward throughthe gear compartment 3| and out through the top of the column, and issecured at its upper end to the clutch actuating lever 25. By moving theclutch lever 25 from side to side, the shaft 14 and pin- -ion 13 arerotated and the rack bar 12 is moved thereby shifting the clutch spoollongitudinally,

68 by means of the yoke 69 to engage either the clutch 63 or the brake18 as may be desired. A detent mechanism, including a spring urgedplunger 15 projecting upward from the bottom of the gear compartment 3|and cooperating with a detent roller 16 carried by the rack bar 12, isprovided to retain the shifting rack 12 in either the clu ch engaging orthe brake engaging posifrom which they may be removed tion. If it isdesired to change the angular position of the starting lever 25, thelever and the shaft 18 may be lifted upward to disengage the teethof'the pinion 13 from the teeth of the rack 12, whereupon the lever maybe turned to the desired position and the pinion teeth re-engaged withthe rack teeth. 1

In order to provide a protected and concealed control connection fromthe motor controlling switch 26 on the starting lever at the top of.the' column to the motor in the motor compartment 24 at the bottom ofthe column, a control cable 11 is led from the switch 26 through ahousing 18 formed within the lever. 25 into the upper end of the hollowcontrol shaft 14, the cable'being'carried downward within the shaftthrough the gear compartment 3|. As shown in Fig. 2, the lower end ofthe hollow shaft 14 is counterbored to telescope over a stationary tube19 which passes upward through and is. fixed in a horizontal dividingwall that separates the gear compartment- 3| from the motor compartment24, the arrangement being such that the telescoping connection betweenthe shaft 14 and the tube 18 prevents lubricating oil in the gearcompartment 3| from entering the tube. .The control cable 11 passingdownward through the control shaft 14 is carried through the tube 19which serves to convey it from the gear compartment 3| downward into themotor compartment 24 for connecting with the driving motor therein. Toprevent the control cable 11 from'being twisted ofi by rotation of theclutch lever 25 through more than one revolution, an abutment or stopmember 8| is provided to engage a stop pin 82 on the clutch shiftingpinion 13 in such manner that turning of the clutch lever 25 is limitedto an angular movement somewhat less than a complete circle.

At the inner end of the inner part of the hollow main driving shaft'62,there is provided a driving bevel pinion 85 which meshes with twosimilar cooperating bevel pinions 86 and 81, shown in Fig. 3, that arerotatably mounted on a shaft 88 journaled at right angles to the maindriving shaft 62, the arrangement being such that the driven pinions 86and 81 are rotated in opposite directions by the driving pinion 85. Asliding clutch spool 89 is splined on the 'shaft 88 between the pinions86 and 81 in a manner to be moved into engagement with either of thepinions to couple it to the shaft 88. The pinions and the sliding clutchspool constitute a reversing mechanism for driving the shaft 88 ineither direction to selectively cause the tool carrying spindle 22 to bedriven in the desired direction of rotation.

As shown in Fig. 2, the reversing clutch spool 89 is engaged by ashifter yoke90 in the form of a pivotally mounted bell crank, one arm ofwhich is engaged by a slidable reversing plunger 9| extending throughthe left side of the machine and provided at its outer end with areversing knob 82 by means of which it may be moved in or out to movethe clutch spool 88 to either of its positions, a spring-pressed detentmechanism 93 being provided for retaining the rod 9| in either its inneror outer position. The bevel pinion 85 on the inner end of the maindriving shaft 62 and the cooperating bevel pinions'86 and 81 constitute,in addition to means for reversing the direction of the spindle, a con-'shaft disposed at right angles to the axis of the spindle 22.

The shaft 88 is rotatably mounted in a speed box 95 which extends withinthe gear compartment 3I of the column through an opening 96 in the leftside thereof, a cover plate or control panel 91 being formed as part ofthe speed box and constituting a closure for the opening 96. As shown inFig. 2, the control panel 91 carries the reversing plunger 9| with itsreversing knob 92, and the pivotally mounted reversing yoke 90, as wellas the speed selecting control lever 30 and the speed indicating dial32.

Referring to Fig. 3, the reversing shaft 88 has hired at one end .apinion 98 which meshes with at which the spindle 22 is operated. Splinedon the shaft I for longitudinal sliding movement is a first gearcouplet. comprising gears IN and I02 joined together and disposedto beselectively meshed respectively with cooperating gears' I 03 and I04fixed on a rotatable intermediate or idler shaft I05 that is journaledin the speed box 95 above and parallel with the shaft I00; A secondslidably mounted couplet on the shaft I00 includes a gear I06 and a'gearI01 disposed to be selectively meshed respectively with cooperatinggears I08 and I09 also fixed on the rotatably' column 20, and that hassplined thereon anaxially slidable gear I II which may be selectivelymeshed with a gear II2 fixed on the shaft I05. Also slidably mounted onthe shaft H0 is a couplet comprising a gear II3 that may be meshed withthe idler gear I03 on the shaft I05, and a gear II4 that may be meshedwith a c0- operating gear II5 also fixed on the idler shaft I05. Thesliding gear III and the couplet gears H3 and H4 constitute a secondaryelement of the variable speed device ,A, and these three gears may beselectively positioned to engage their cooperating gears respectivelyfor transmitting power from the shaft I05 to the shaft I I0 at any oneof three ratios.

As the primary element of the variable speed device A is capable of fourdifferent speed rates, and the secondary element is capable of threerates, it is evident that the shaft IIO may be driven at any one oftwelve speed rates by suitably engaging diiferent ones of the slidinggears "in the primary and in the secondary elements of the variablespeed device with their cooperating gears in the idler gear cluster onthe shaft I05. For the sake of clearness in the drawings, all of thesliding gearsof the variable speed device A are shown in Fig. 3 inout-of-mesh or neutral position, but-it is to be understoodlthat thespeed selecting lever and the indicating dial 32 do not provide for anopera 'ng condition with the gears in' the neutral posiim and that forany operating position of the dial, one of the gears of the primaryelement and one of the I gears of the secondary element are in mesh withcooperating gears of the idler cluster.

As shown in Fig. 3, the shaft H0 is disposed parallel withand directlybelow the cutter spindle' 22, and power is transmitted from the shaft II0 to the spindle 22 by means of a range changer generally designated bythe letter B. The range changer B includes a couplet splined on theforward end of the shaft IIO for longitudinal movement relative theretoand constituted by a relatively large range drive gear wheel I20disposed to be meshed with a relatively small gear wheel I2I fixed onthe spindle 22, and a relatively small rangedrive pinion I 22 disposedto be meshed with a large gear wheel I23 fixed on the spindle 22 closeto its forward end. The gears of the range changer B are so proportionedthat they may be shifted selectively to change the speed of the spindle22 by a relatively large step to effect operation of the spindle 22 ineither a fast range of a slow range. The proportions of the gearing aremade such that each of the two ranges includes all of the twelve speedchanges which may be effected by the variable speed device A, andconsequently the spindle 22 may be operated at any one of twenty-fourdifferent speeds by adjusting the variable speed device A and the rangechanger B cooperatively.

For adjusting the variable speed device A, there is provided a camactuated gear shifting mechanism constituting a mechanical linkagearranged to be directly operated by the speedselecting lever 30 andfunctioning to positively shift the sliding gears of the variable speeddevice in such manner .that the twelve speeds of the series may beeffected in predetermined order. The shifting mechanism is so arrangedthat the gears are shifted in manner to avoid possibility of locking themechanism" by engaging more than one gear of the primary element on theshaft I00 or more than one gear of the secondary element on the shaftIIO with a cooperon the periphery of a primary speed changing cam I33fixed on a stub shaft I34 that is journaledin the cover plate 91. Asshown in the detail view, Fig. 10, the cam plate I33 is provided with acam track or groove I35 cooperating with IM and I 02 of the firstcouplet in the primary shifting element, and is operative upon movementof the shifting arm I38 by the cam groove I35 acting upon the camfollower I36, to shift the gear IN or the gear I02 into meshingengagement with the respective cooperating gear I03 or I04 of the idlergear cluster.

The cam follower I3! is carriedbn one arm of a bell crank shifting leverI, which is pivotally mounted on the; inside of the cover plate 91and'that engages with the end of its other variable speed device A. Asmay be seen in Figs. 9

arm ashifting fork I42 also slidably mounted on the guide rod I40. Theshifting fork I42 is generally similar to the shifting fork I39 andis.en-

gaged between the gears I06 and I01 of the second couplet in the primaryshifting element, as shown in Fig. 3, for shifting the) gear I06 or thegear I01 into engagement with the gear I08 or the gear I09 respectivelyof the idler cluster. As may be seen in Fig. 10, the cam groove I35 isprovided with a semi-circular section which iunctions to retain one ofthe couplets in neutral position while the other couplet is beingshifted one way or the other by the remaining non-concentric section ofthe cam groove, thereby avoiding engagement of both couplets with theidler cluster at the same time.

For shifting the gears of the secondary element in the variable speeddevice A, there is provided .a secondary cam plate I43 mounted on ashaft I44 directly above and parallel with the shaft I34. The secondarycam plate I43 is operatively connected with the primary cam plate I33 bymeans of intermittent gearing constituting a Geneva movement arranged insuch manner that the cam plate I43 is turned through one-third ofarevolution at the end 'of eachcomplete revolution of the cam plate I33.As may be seen in Fig. 10, the cam plate I33 is provided onits peripherybeside but spaced from the gear I32 with a discontinuous gear element,M5. the teeth of which mesh with a mutilated gear I46 secured to the camdisk I43 and cooperating in manner to eifect the desired intermittentmovement. 7

Referring now to Figs. 9, l2, and 13, it will be seen that the secondarycam plate I43 is provided in the inwardly presented face thereof with acam track or groove I48 that is engaged by a cooperating follower I49.As best shown in the top view, Fig. 13, the cam follower I49 is securedto a shifting fork I50 that is slidably mounted on a guiderod I5I fixedin the speed box 95. As shown, the shifting fork I50 engages a grooveI52 of the gear couplet formed by the gears'I-I3 and H4 of the secondaryelement, for shifting the gears into engagement respectively with thecooperating gears I03 and H5 ofthe idler cluster. The other or outerface of the cam plate I43 is also a cam disk, being provided with a camtrack or groove I55 cooperating with a cam follower I5'6. As shown inFigs, 8, l2, and 13, the cam follower I56 is carried on the end of onearm of a bell crank shifting lever I51 pivotally mounted on a pin I58secured to the speed box 9 5. The other arm of the bell crank lever I51engages at its end with a shifting fork I59 also slidably mounted on theguide rod I5I and disposed to engage a groove I60 in the hub of theshiftable gear III, for shifting the gearinto or out of engagement withthe gear I I 2 of the idler cluster.

The gearing interconnecting the speed selecting lever 30 with the camplates I33 and I43 is so proportioned that for each complete turn of thelever 30, one c." the gears inthe variable speed device is shifted toelfect a change from one speed to the next. Consequently twelve turns ofthe 2, 3, and 14, the hub of the couplet constituted by the range changegear I20 and the range change pinion I22, is provided with a shiftinggroovev I62 that is engaged by a shifting fork I63. The fork I63-ismounted on the end of a piston rod I64 provided with a piston I65working in-a hydraulic cylinder I66, as best shown in Fig. 14.

Referring again to Fig. 5,- the hydraulic shifting mechanism for. therange changer B is con-.

trolled by means of a range changing valve I10 that is mounted on a stubshaft I1I journaled in the'control panel 91 just back of the upper edgeof the speed indicating dial 32, and that functions to preselect theadjustment of the range changer. For actuating the range changing valveI10, .the shaft "I is provided with an arm I12 .carrying at its end acam follower I13 which engages a cam groove or track I14 on the innersurface of the speed selectingdial 32, as best shown in Fig. 11.The-speed indicating dial 32 is rotatably mounted in the control panel91 and has secured to its inner side a gear ring I15 which meshes witha. cooperating pinion I16 on the outer end of the cam operating shaftI34, whereby the speed indicating di-al is operatively connected withthe speed selecting lever 30 and the cam groove I14 is coordinated withthe cam grooves actuating the shifting mechanism of the variable speeddevice A.

Since the total number of speeds efiected by y-the variable speed deviceA and range changer B in cooperation is twenty-four, the gearingconnecting the. speed selecting crank 30 with the speed indicating dial32 is of such ratio that it requires twenty-four revolutions of thecrank 30 to turn the dial 32 through one complete revolution, the dialbeing provided with twenty-four numerals constituting speed indicia,which cooperate individually with a stationary indicator I80 to show thespeed at which the spindle 22 will operate at any selected settingof thespeed changing transmission. As the range changer B remains in oneposi-.

tion throughout one entire series of speeds effected by the variablespeed device A, and in its other position throughout another entireseries of speeds effected by the variable speed device A, the cam grooveI14 in the rotatable speed indicating dial 32 is so shapedras shown inFig.

11, that the range changer control valve I10 is held in one positionthroughout one-half revolution of the speed indicating dial 32 and inits other position throughout the other half revolution of the dial, thetwo positions being shown in Figs. -6 and '1.

Forpositioning the speed selecting lever 30 after it has been turned toshift the gearing, the' lever is provided with an operating knob andlatching device constituted. by a spring-pressed locking plunger I02that is adapted to enter a locating hole l83 in a stationary memberconlever 30 are required to effect all .of the twelve.

olution.

For shifting the range changer B, there is provided a hydraulicallyactuated mechanism which is controlled by the speed-selecting lever 30independently of but in coordinated relationship with the cam actuatedshifting mechanism for the stitutingpart of the control panel 91. Toinsure that the gears will not be shifted while power is beingtransmitted through them, and to simplify the shifting operation, acontrol system is so arranged that the main driving clutch 63 isautomatically disengaged as aprerequisite to'speed selecting movement ofthe layer 30. For this purpose, the clutch control is arranged to beactuated by movement of the locking plunger I82 in withdrawing from thepositioning hole I83 when the lever 30 is unlatched for a turningmovement. In addition to disengaging the main clutch, the nnlatchingmovement of the plunger I82 effects engagement of a slow speed auxiliarydrive for the gearing to facilitate shifting of the gears, and alsorenders the hydraulic shifting mechanism for the range changer Binoperative to prevent shifting of the range changer until after theshifting of the variable speed device has been completed.

As shown in'Fig. 5, the locking plunger I82 is provided with a grooveI84 that isen'gaged by one end of a valve operating arm I85 that isdisposed within the hollow speed selecting lever 30 and pivotallymounted midway of its length. The other end of the arm I 85 engages agroove I86 in a valve stem I81 that is slidably mounted within thehollow speed selecting shaft I30, and is connected by a valve pin I88with a control valve plunger I89 that slides within a valve cas-' ingI90 carried by the control panel. When the locking plunger I82 is movedoutwardly'to un-' latch the lever 30, the valve stem I8I and valveplunger I89 are moved inwardly to the position shown in Fig. 14. a

With the locking plunger I82 unlatched and the valve plunger I89 in theinner position preparatory to a shifting movement of the speed selectinglever 30, the various hydraulic control circuits are established asindicated in the control diagram, Fig. 14. 'As there shown, the ac-"tuating fluid, which is ordinarily the lubricating under pressurepasses through a longitudinal passageway 2I4 to the left end of thecylinder, building up suflicient pressure therein to oppose the springurged detent plunger I5 and to preport 2|: moves out of register withthe cylinders port 201 and into register with a cylinder port 2I5,through which the oil may escape. By-this arrangement, a hydraulic lockis effected and the piston 204 is held in a position in which the clutch63 is disengaged and the brake cone I0 is held out of engagement withthe braking surface II.

The means for effecting slow speed rotation of the transmissionmechanism to facilitate gear shifting embodies the principles describedand claimed in the co-pending application of Walter M-. Pohl and JosephB. Armitage, filed January 27, 1933, Serial No. 653,872, and entitledMachine tool transmission and control, which issued March 8, 1938, asPatent No. 2,110,173 and was reissued April 23, 1940, as Re. 21,434. As

, the slow speed auxiliary drive mechanism should a conduit I91 to whichis connected a-relief valve I98'for relieving excessive pressure in thesystem. The conduit I9'I leads to a port I99 in the valve casing I90which communicates through a groove 200 inthe valve plunger I89 with aport 20I from which a conduit 20 2 leads to a clutch disengaging orneutralizing cylinder 203. Within the cylinder 203 is a cooperatingpiston 204 having a piston rod 205 that is connected to the clutchshifting'yoke 69.

i Assuming that the machine is running when the locking plunger I82 iswithdrawn prerequisite to effecting a speed changing movement, the mainclutch 63 being engaged, the clutch shifting piston 204 would be at theright end of the cylinder 203, and oil under pressure in the conduit 202would flow through a circumferential port 201 in the wall of thecylinder 203, into a port 208 in the piston and thence through alongitudinal passageway 209 therein to'the right end of the cylinder,thereby exerting force to move the not be engaged until after both themain clutch and the brake are moved to disengaged position by the piston204, a hydraulic control circuit for engaging the auxiliary drive isarranged to become effective only after the piston 204 has moved to theneutralizing position, as shown in Fig. 14. As shown, the piston 204 isprovided with a valve port 2! which establishes communication betweenthe cylinder port 201 and a cylinder port 220 when the piston is in theneutralizing position with both the clutch and the brake disengaged.From the cylinder port 220, the oil flows through a conduit 22I into acylinder 222 having a cooperating piston 223. Pressure in the cylin-.

der 222 forces the piston 223 to the right against til the detentroller,l6 ln the rack 'bar I2 passes over the center of thespring-pressed plunger I5, whereuponthe detent mechanism will urge thepiston 204 to the left, moving the piston port 208 out of register withthe cylinder port 201 and into register with a cylinder port 2I2 open tothe atmosphere, thus cutting off the source of pressure to theright endof the'cylinder' and permitting movement of the piston to the left.

To prevent the detent mechanism from moving the clutch shiftingmechanism intofbrake engaging position, the piston. 2 04 isproyided witha port 2I3 which moves into'r'e'gister with the circumferential cylinderport 201, whereupon oil when the planetary sear couplet is gyrated withaclutch operating plate and plunger 224, fore ing the plunger to theright against the pressure.

of a spring'225 to engage a friction clutch 226 constituting part of theslow speedauxiliary drive mechanism.

As shown in Fig. 14, power for turning the auxiliary drive mechanism isderived from the gear wheel 59 on the constantly rotating pulley sleeve51 that meshes with and drives a gear wheel 230 which is rotatablymounted on a shaft 23I concentric with the friction clutch 226. The gearwheel 230 is provided with an eccentrically disposed hub or sleeve 232shown in transverse section in Figs. 15 and 16 (sheet 1), upon which isrotatably mounted aplanetary gear couplet 233 in manner to be gyrated orrevolved bodily in a circular path about the axis of the shaft 23l whenthe gear 230 is rotated.

The planetary gear couplet 233 includes a gear 234 and a gear 235. Asmay best be seen in Fig. 15, the gear 234 meshes with and rolls within astationary internal gear 231, which is attached to the bracket 58 by capscrews 238. As shown in Fig. 16, the planetary gear 235 of the couplet233 meshes with-and rolls within an internal gear 240 which is keyed tothe shaft 23I. The ratio of the number of teeth in the internal gears tothe number of teeth on the planetary gears is suchthat diflerentialaction occurs in the internal gears, with the result that the internalgear 240 on the shaft 23 I is caused to progress relative to thestationary internal gear 231, thereby turning the shaft 23I, but atgreatly reduced speed.

As may be seen in 2 of the clutch 226 is keyed to the shaft 23I andanother element 242, constituting an -enclosing casing, is provided onits periphery with gear teeth 243 constituting a gear wheel that may becoupled to the shaft 23I by engaging the clutch 226, in manner to rotatewith it at slow speed. The gear teeth 243 mesh with a cooperating gear244 that is secured on the main driv-' ing shaft 62 and that operates toturn the shaft and the gearing of the variable speed device at a low.speed when the clutch 226 is engaged, to facilitate engagement of thesliding gears of the variable speed device A when they are shifted bythe cam actuated gear shifting mechanism. If the machine is running atthe time that the locking plunger I82 is withdrawn to initiate a speedselecting movement, the tool spindle may continue turning after the mainclutch moves to disengaged position. In this event, the auxiliaryfriction clutch 226, upon being engaged,

functions first as a brake to quickly retard the spindle driving trainto the slow speed for facilitating gear shifting.

In changing from one speed to another, the

speed selecting lever 30 may be turned through .as many completerevolutions as may be necessary to turn the dial 32 a sufficientdistance to move the indicia representing the desired speed intoregister with the indicator I00. As the lever 30 is turned, the slidinggears of thevariable speed device A are moved successively into and outof mesh by the cam actuating mechanismwhile they are being turned slowlyby the aux iliary slow speed drive mechanism, to prevent the gears fromengaging tooth on tooth, and

likewise the range changing valve I may beturned from one position tothe other by the cam groove I14 in the dial 32.

When the desired speed has been selected by the lever 30, the lockingpin I82 is again engaged in the positioning hole I83, the latchingmovement resulting in the valve I89 being moved to the left within thevalve casing I90 to'the position shown in Fig. 5. With the valve I89 inthe left position, a land 246 of the valve is interposed between thepressure port I99 and the port 20I leading to the clutch disengagingcylinder, the port 20I then being open to the atmosphere as shown inFig. 5. Thefiuid under pressure in the slow speed clutch engagingcylinder 222 then escapes through the conduit 22I, valve ports 220, 2I9,and 201, and through the conduit 202 and the 'port -20I, therebypermitting the spring 225 to disengage the clutch 226, thusdisconnecting the auxiliary slow speed drive. Likewise, the oil underpressure in the left end of the cylinder 203 escapes through. the pistonthe drawing, one'element tion shown'in Figs. 14 and '7, oil underpressure from the 'port 25I passes through 'an arcuate groove ,253 inthe valve I10 to a port 254, from which a conduit 255 leads'to the leftend of the range changing cylinder I66, exerting pressure therein toforce-the piston I65 to the right, as

shown in Fig. 14, and. moving the pinion I22 of escapes through aconduit 256 which leads to a port 251 in the valve plate 252 and thencethrough another arcuate groove 258 in the valve I10 to an exhaust port259, from which it escapes through a conduit 260.. When th pistonarrives at the end of its stroke, it uncovers a port 262 at the middleof the cylinder, from which the 011 under pressure in the cylinderescapes through a conduit 263 that may lead to the lubricating system ofthe machine.

If the range changing valve I10 is turned by the cam groove I14 of theindicating dial 32 during a shifting operation to the position shown inFig. 6, the oil under pressure entering the valve through the port 25Iwill flow through the groove 258 into the port 251 and thence throughthe conduit 256 to-the right end of the cylinder I65 and will move thepiston I65 to the left to .the position indicated in dotted lines inFig. 14, thereby meshing the gear .I20 of therange changer B with thegear IN on the spindle 22 for driving the spindle in the high speedrange. Oil in the left end of the cylinder I66-wil1 then be forced outthrough the conduit 255 and the port 254 into the valve groove 253 whichconnects with the exhaust port 259 for exhaust through the conduit 260.stroke to the left, the piston I65 again uncovers the port 262 topermit'the oil to flow into the conduit 263.

After the sliding gears of the variable speed device A have been shiftedby the speed selecting lever 30, and the gears of the range changer Bhave been subsequently shifted hydraulically in accordance with thesetting of the valve I10, the machine may be placed in operation at theselected speed by moving the starting lever'25 to re-engage the mainfriction clutch 63. v

From the foregoing explanation of the construction and operation of apreferred embodiment of the invention, it is apparent that therepassageway 2I4, the port 2I3, and the annular cylinder port 201 into theconduit 202 and-out through the port "20l, permitting the spring detentmechanism to move the piston 204 to the left, thereby engaging the brakecone 10 with the brake member H and retaining the starting lever 25 inthe stop position. 7

With the valve I89 in the left position, as shown in Fig. 5, the valvegroove 200 establishes communication from the pump 6|, through theconduit l91, and the pressure port I99, to'. a port249 in the valvecasing fromwhich a conduit 250 leads to a port 25I in a valve plate 252,which cooperates with the range changing valve I10. With the rangechanging valve I10 .in the posihas been provided an improved-millingmachine having a speed changing transmission mechanism capable ofrapidly and positively effecting a change in speed without danger ofinjury occurring to the mechanism through carelessness in performing theshifting operation.

Although only one embodiment of this invention has been shown anddescribed as exemplary of the manner in which it may be practiced, it

will be apparent to others skilled in the art to which the inventionrelates that various modifi cations of the structure herein described indetail may be effected without departing from the spirit and scope ofthe invention as defined in the subjoined claims. v

I claim as my invention:

1. In a transmission mechanism, thecombina- At the end of its' tion witha manually'operated speed changing device and a power operated speedchanging device arranged in series relationship, of a manually actuatedcontrol element eonnectedto shift said manually operated speed changingdevice and operative to pre-select the mode of operation of said poweroperated speed changing device, means associated with said controlelement and operative to prevent actuation of said power operated speedchanging device while said manually operated speed changing device isbeing shifted, and means associated with said control element andeffective to actuate said power operated speed changing device inaccordance with the pre-selected mode of operation upon completion ofshifting movement of said control element.

' 2. In a speed changing transmission and con-. trol mechanism for amachine tool, the combination with a variable speed device and a rangechanger arranged in series relationship, of a speed selecting deviceoperative upon speed selecting movement to adjust said variable speeddevice and to pre select an adjustment for said range changer, and'means operative subsequent to completion of a speed selecting movementof said sp ed selecting device to effect adjustment of said rangechanger in accordance with the adjustment pre-selected during saidspeed, se-

lecting movement.

3.In a milling machine speed changing transmission mechanism, thecombination with a plurality of shiftable gears, of hydraulicallyactuated means for shifting some of said. gears, mechanically actuatedmeans for shifting others of said gears, a control member operativelyconnected to directly actuate said mechanical gel r shifting means, andhydraulic control means actuated by said control member and operative tocontrol said hydraulically actuated gear shifting means, whereby shouldsaid hydraulically shifted gears fail to mesh shifting pressure will bemaintained upon them without interfering with movement of said controlmember.

4. In a speed changing transmission and control mechanism for a machinetool, the combination with a variable speed device and a range changerarranged in series relationship, of a speed selecting device operativeupon speed selecting movement to adjust said variable speed device andto pre-select an adjustment for said range changer, and means operativepre-requisite' to a speed selecting movement of said selecting device toprevent adjustment of said range changer by said speed selecting device,and operative subsequent to a speed selecting movement to'efiectadjustment of said range changer in accordance with the adjustmentpre-selected said range changing gearing, said hydraulic actuatingdevice being arranged to exert pressure tomesh said range changinggearing without interfering with movementof said mechanical linkage inmeshing said variable speed gearing.

6; A sldw speed driving mechanism for the speed changing transmission ofa machine tool, comprising a driving element normally operating atrelatively high speed, a gyratory gear couplet.

arranged to be gyrated by said driving element, a

stationary internal gear meshing with one gear of said gyratory couplet,a rotatably mounted internal gear meshing with the other gear of saidgyratory couplet, the ratios of said internal gears-and said gyratorycouplet gears being such that'said rotatable internal gear is caused toprogress at a relatively slow rate of speed, and means including a.friction clutch disposed to selectively connect. said rotatableinternal gear to the machine tool transmission for rotating it slowly tofacilitate gear shifting.

7.-In a machine tool provided with a speedcha nging transmissionmechanism having a plurality of parts, the, combination with a singlespeed-selecting member for controlling two of said parts, of meansoperative pre-requisite to a speed-selecting movement of said member torender one part of said transmission mechanism non-responsive tomovement of said member, and means operative subsequent to aspeed-selecting movement of said member to eifect response of saidpreviously non-responsive part of said transmission mechanism inaccordance with an adjustment thereof pre-selected by thespeed-selecting movement of 'said member.

8. In a machine tool, the combination with a P able element, a hollowlever operatively connected to control said clutch, a manually operableswitch carried by said clutch lever, and an electrical control cableextending from 'said switch through said hollow lever and operativelyconnected to control said motor.

9. A machine tool comprising a frame, a movable working elernent carriedby said frame, a motor carried by said frame for actuating said movableelement, means operatively connecting said motor to saidelementincluding a clutch, a hollow clutch operating shaft, a manuallyoperable hollow clutch lever carried by said hollow clutch shaft andoperatively connected thereby to actuate said clutch, a manuallyoperable electric switch carried by said hollow clutch lever, and anelectrical control cable extending from said switch through said' hollowclutch lever and shaft and operatively connected to control s d motor.

10. In a milling machine having a hollow column provided with a dividingwall disposed to define at one side thereof a motor compartment and atthe other side thereof a gear compart- 'ment, and movable to actuateapparatus therein,

a tubular member-extending through said dividing walland connecting saidtubular control shaft with said motor compartment, a control switchcarried by said control shaft outside of said, column, and an electricalcontrol cable extending from said switch through said. tubular controlshaft and said tubular connecting member into said motor compartment.

11. In a machine tool speed changing mechanism, the combination with avariable speed device and a range changing device cooperatively arrangedto control thespeed of; rotation of a driven element, of a speedselecting control mem-' ber for adjusting both {said variable speeddevice and said range changing device, mechanically actuated meansoperatively connecting said speed.

that should said hydraulically actuating rangechanging device fail tofunction actuating pressure will be maintained upon it withoutinterfering with the movement of said speed selecting control member.

12. In a machine tool transmission mechanism,

the combination with a variable speed mechanism and a range changingmechanism constituting a speed changing apparatus, of a speed indicatingdevice, a speed selecting lever, mechanism operatively connecting saidspeed selecting lever I to said variable speed mechanism and to saidspeed indicating device, and hydraulic actuating means operativelyconnecting said speed selecting lever to said range changing mechanism,whereby said variable speed mechanism, said range changing mechanism-andsaid speed indicating device may be operated inpredetermined.relationship to establish a desired speed and to indicatethe established speed, said hydraulically actuating means functioning toexert a continuous shifting pressure upon said range changing mechanismshould it resist adjustment without interfering with further operationof said speed selecting lever.

13. In a machine tool transmission and control mechanism, thecombination with a speed changing mechanism and driving means thereforincluding a disconnecting clutch, of hydraulic actuating mechanism foradjusting said speed changing mechanism, hydraulic actuating mechanismfor actuating said clutch, a speed selecting 14. In a machine tooltransmission and con-- trol mechanism, the combination with a speedchanging mechanism including a variable speed device and a rangechanging device, and driving mechanism therefor including a isconnectingclutch, of a speed selecting lever, means operative upon speedselecting'movement of said lever to adjust said variable speed deviceand to preselect an adjustment of said range changing device, meansoperative by said speed selecting lever prior to speed-selectingmovement thereof to disengage said clutch and to render saidrangechanging device non-responsive to said speedseleoting m ovement,and means operative by said speed selecting lever afterspeed-selecting-movement thereof to efiect adjustment of said rangechanging device in accordance with the adjustment pre-selected by saidspeed-selecting movement.

15. In a speed changing transmission mechanism for a machine tl,"thecombination with a source of power, a disconnecting clutch, a variablespeed device, and a range changing device arranged in seriesrelationship; of a speed selecting element for controlling said speedchanging transmission mechanism, a latching device disposed to retainsaid element any one of several speed determining positions, ,mechanisinoperatively connected with said speed selecting element and efiective toadjust said variable speed,

, device upon speed-selecting movement of said changing device, meansoperative upon speed-. selecting movement" of said element to pre-selectan adjustment of said range changing device to be subsequently efiectedby said adjusting mechanism, meansoperative upon unlatching movementofsaid element latching device to disengage said clutch and to render saidrange changing mechanism non-responsive to speed-selecting movement ofsaid element, and means operaptive upon latching movement of saidelement latching device to actuate said mechanism for adjusting saidrange changing device to effect adjustment thereof in accordance withthe preselected adjustment established by said speedselecting element. 4

16. In a machine tool speed changing transmission mechanism, thecombination with a source of power, a clutch, a variable speed device,and a range changer; of hydraulically actuated means for disengagingsaid clutch, hydraulically actuated means for adjusting saidrange-changer, a valve disposed to control said range changer adjustingmeans, a speed selecting control device arranged upon speed selectingmovement thereof to'directly actuate said variable speed device and toposition said control valve for predetermining a subsequent adjustmentof said range changer, and a valve operative uponinitiating aspeed-selecting movement of said speed selecting control device toconnect said hydraulically actuated means for disengaging said clutchand to 4 disconnect said hydraulically actuated means for adjusting saidrange changer, said valve being operative upon completing aspeed-selecting movement of said speed selecting control device toconnect said hydraulically actuated means for adjusting said rangechanger to thereby effect with the previously selected position of saidrange changer control valve. I

17. In a machine tool transmission and control mechanism, thecombination with a driven element, speed changing mechanism including 'arange changer and a variable speed device connected in seriesrelationship to drive said driven element, a clutch disposed toselectively drive said variable speed mechanism, and a source of powerof said clutch, hydraulically actuated means arranged to adjust saidrange changer, a valve disposed -to control the adjustment of said rangech n er by said hydraulically actuated means, a speed selecting andindicating mechanism including a control lever and a speed indicatingdial actuated in accordance with movements of said to latch saidspeed-selecting mechanism in.any

element, mechanism for adjusting said range adjustment of said rangechanger in accordance connected to drive said clutch; of hydraulically vactuatedmeans arranged to effect disengagement lever, a latching deviceassociated with said lever to adjust the position of said range changercontrol valve, and a valve associated with said latching device andoperative upon latching movement thereof to actuate said hydraulic rangechanger adjusting means to adjust said range changer in accordance withthe pre-selected position of said range changer control valve.

18. In a transmission and control mechanism for a machine tool, thecombination with a variable speed device and a range changer connectedin series relationship, of a speed-selecting member having alatchlng'device arranged to latch said member in any one ofseveral'positions corresponding to the'several speeds that may be ef-'fected ,by said variable speed device and said range changercooperatively, means responsive to unlatching movement of said latchingdevice to lock said range changer to prevent adjustment thereof, meansresponsive to movement of said speed selecting member to adjust saidvariable speed device and to pre-select an adjustment of said rangechanger, and means effective upon subsequent latching movement of saidlatching:

selectively engageable when said main clutch is disengaged to effect adirect connection with said, mechanism to drive it at slow speed, and ahydraulically actuated control system operative prior to a gear shiftingadjustment to disengage said main clutch and to engage said frictionclutch, said friction clutch functioning as a brake in manner to reducethe speed of said mechanism quickly to a low rate adapted tofacilitateshifting of said gearing.

20. In a machine tool having an adjustable rate changer includingshiftable gearing, the combination with main driving means including amain clutch selectively engageable to drive'said gearing, at normaloperating speed, of an auxiliary low speed driving means including anauxiliary friction clutch, and a control system arranged to engage saidauxiliary friction clutch upon said main clutch being disengaged, saidfriction clutch functioning to retard said gearing quickly from itsnormal operating speed and to drive it at a low rate of speed tofacilitate gear shifting.

21. In a machine tool having an adjustable power transmission mechanism,a primary drivtransmission mechanism at normal operating speed, anauxiliary slow speed driving means op- .ing means selectivelyengag'eableto drive said erative to drive said transmission mechanism at aspeedadapted to facilitate adjustment thereof,

a friction clutch selectively engageable to connect I said auxiliarydriving means directly to saidpower brake to reduce the speed of saidpower'transmission promptly, to. thejslowspeed for facilitatingadjustment.

22. In a machine tool havingi' anf adjustable right angle from saidtransverse driving shaft to' -member to render one of said mechanismsnon-,

transmission mechanism at normal operating speed; an auxiliary slowspeed driving means operative to drive said transmission mechanism at aspeed adapted to facilitate adjustment thereof, a

friction clutch selectively engageable to connect said auxiliary drivingmeans directly to said Dower transmission mechanism in such manner thatsaid friction clutch functions as a brake to reduce the speed of saidpower transmission mechanism promptly to the slow speed for facilitatingadjustment, and control means disposed power transmission mechanism insuch manner,

that said friction clutch functions as a brake to reduce the speed ofsaid power transmissionmechanism promptly to the slow speed forfacilitating adjustment, control means disposed to adjust said powertransmission mechanism and operative prerequisite to anadjustment ofsaid mechanism todisengage said primary driving means and to engage saidauxiliary friction clutch automatically, and another control device forselectively engaging or disengaging said primary driving meansindependently of said auxiliary friction clutch.

24. A slow speed driving mechanism for turning the speed changingtransmission of a machine tool to facilitate adjustment thereof,comprising a driving element normally operating at relatively high speedand selectively connectible to drivesaid speed changing transmission at'normal speed, a gear reduction train connected to be driven by saiddriving element'and operative to provide a relatively slow rate ofspeed, and a friction clutchdisposed to connect said gear reductiontrain directly to said speed changing transmission for checking itsspeed and for rotating it slowly while it is being adjusted- 25. In amilling machine having a column and a tool supporting spindle mountedhorizontally in said column longitudinally thereof, the combination witha driving shaft disposed crosswise of said column and transversely ofsaid spindle, of transmission means including a bevel gear reversingmechanism operatively connecting said driving shaft to said spindle,said bevel gear reversing mechanism functioning both for selectivelyreversing the direction of rotation of said spindle and for transmittingpower through a said spindle.

26. In a machine tool provided with a plurality of speed changingtransmission mechanism; ar-

ranged in series relationship, a single speedselecting member forcontrolling two of said speed changing mechanisms, means operativeprerequisite to a speed-selecting movement of said responsive to saidspeed-selecting movement and power transmission mechanism, aJprimarydrivns means selectivelygengageable to drive; said to cause slowrotation of, another of said mechanisms to facilitate adjustmentthereof, and means operative subsequent to the speed-selecting movesaidspeed changing mechanism, and means oper ative by said speed selectingcontrol mechanism to disengage said disconnecting device and to engagesaid slow speed friction clutch to connect saidslow speed mechanismdirectly to said speed changing mechanism, prior to a speed-selectingadjustment thereof, whereby said speed changing mechanism may bedisconnected from its driving mechanism and its speed promptly reducedby engagement of said fric tion clutch to that at which the subsequentspeed-selecting adjustment is facilitated.

28. In a machine tool transmission and control mechanism, thecombination with a speed chang-. ing mechanism including a variablespeed device and a range changing device and driving mechanism thereforincluding a disconnecting clutch and a slow speed driving device, of aspeed-selecting lever, means operative by said speed-selecting leverprerequisite to a speed-selecting movement thereof to disengage saidclutch and engage said slow speed driving device and to render saidrange-changing device non-responsive to said speed-selecting movement,means operative upon speed-selecting movement of said lever to adjustsaid variable speed device While it is turning slowly and to pre-selectan adjustment of said range changing device, and means operative by,said speed-selecting lever subsequent to a speedselecting movementthereof to disengage said slow speed driving device and to effectactuation of said range changing device in accordance with theadjustment thereof pre-selected by said speedselecting movement.

. 29, In a machine tool speed changing transmission mechanism, thecombination with a source of power, a clutch driven by said source ofpower,

a variable speed device and a range changer connected to be driven bysaid clutch, and a slow speed driving device, of hydraulically actuatedmeans for adjusting said range changer, a valve disposed to control saidrange changer adjusting means, a speed selecting control device arrangedto actuate said variable speed device directly and to position saidcontrol valve for predetermining a subsequent adjustment of said rangechanger, and means operative upon initiating a speed-selecting movementof said control device to effect disengagement of said clutch andengagement of said slow speed driving device and to disconnect saidhydraulically actuated means for adjusting said range changer, saidmeans being operative upon completion of a speed-selecting movement ofsaid control device to disengage said slow speed driving device and toconnect said hydraulically actuated means for adjusting said rangechanger to thereby effect adjustment of said range changer in accordancewith the previously selected position of said control valve. Q

30. In a transmission and control mechanism for a machine tool, thecombination with a variable speed device and a range changer connectedin series relationship, of a speed-selecting member having a latchingdevice arranged to latch said member in any one. of several positionscorresponding to the several-speeds that may be effected by saidvariable speed device and said range changer cooperatively, meansresponsive to unlatching movement of said latching device to cause slowrotation of said variable speed device and to lock said range changer toprevent adjustment thereof, means responsive to movement of said speedselecting member to adjust said vari able speed device while it isrotating slowly and to pre-select an adjustment of said range changer,and means effective upon subsequent latching movement of said latchingdevice to discontinue slow rotation of said variable speed device and toactuate said range changer in accordance with the adjustmentpre-selected by said speed-selecting member.

31. In a speed changing transmission and control mechanism for a machinetool, the combination with a variable speed device and a range changerarranged in series relationship, of a speed selecting device operativeupon speed selecting movement to adjust said variable speed device andto pre-select an adjustment for said range changer, means operativeprerequisite to a speed'selecting movement of said selecting device toturn said variable speed device slowly for facilitating adjustmentthereof, and means operative to prevent adjustment of said range changeruntil after said speed: selecting movement has been completed.

32. In a milling machine speed changing transmission mechanism having aplurality of shiftable gears, mechanically actuated means for shiftingsome of said gears, a slow speed driving mechanism for turning saidgears to facilitate shifting thereof, hydraulically actuated means forshifting others of said gears, and a control member operativelyconnected to actuate said mechanical gear shifting means and to controlsaid hydraulically actuated gear shifting means, whereby should said"hydraulically shifted gears fail to mesh shifting pressure'may bemaintained upon them without interfering with further operation of saidcontrol member.

33. In a rate change and control mechanism the combination of first andsecond rate change devices in serial driving relation and collectivelyadjustable to effect a variety of rate change driv-- ing ratios, a speedselector adjustable to different positions respectively corresponding todifierent of said ratios, a first shifter means controlled from saidselector for directly adjusting said first rate change device inaccirdance with the position of said selector, and a second shiftermeans controlled from said selector for adjusting said second ratechange device in accordance with the position of said selector, saidsecond shifter means including means delaying operation thereof untilcompletionof the operation of said first shifter lector and operative toeffect delayed adjustment of another of said rate changing devices inaccordance'with the final position of said rate selector.

35. A machine tool power transmission and control mechanism, comprisinga plurality of rate while adjusting it.

changing devices, a manually operable rate selector movable to effectdirect manual adjustment of one of said rate changing devices, and poweroperated means responsive to said rate selector and functioning toefiect delayed adjustment of another of said rate changing devices inaccordance with the final position of said rate selector.

36. A machine tool power transmission and control mechanism, comprisinga plurality of rate changing devices, a single selector operative toeifect coordinated adjustment of said rate changing devices, a shifterdirectly operated by said selector and functioning to shift one of saidrate changing devices directly in accordance with movement of, saidselector, :3, power operated shifter arranged to effect power shiftingof another of said rate changing devices, and a delayed action controldevice operative in response to movement of said selector andfunctioning to energize said power operated shifter subsequent tocompletion of direct shifting of said first rate changing device foreffecting delayed power shifting of said other rate changing device inaccordance with the position of said selector.

. 37. A machine tool power transmission and control mechanism,comprising a plurality of rate changing devices, a manually operablerate selector movable to effect directmanual adjustment of one of saidrate changing devices, and

power operated means responsive to said rate seactuated shifterresponsive to said selector and disposed to effect power adjustment ofsaid range changing device in coordination with adjustment of said speedchanging device, whereby operation of said transmission mechanism may beeffected in either speed series.

39. .A machine tool power transmission and control mechanism, comprisinga speed changing devicefa range changing device cooperating with saidspeed changing device to provide for operation in a low or a high seriesof speeds, a single speed selector disposed to effect direct adjustmentof said speed changing device, a power actuated shifter disposed toeffect power adjustment of said range changing device, and control meansresponsive to said selector and operative subsequent to completion ofadjustment of said speed changing device to effect coordinated poweradjustment of said range changing device in accordance with the settingof said selector. 40. In a machine tool, a speed changing transmissionmechanism including a plurality of variablespeed devices arranged inseries relationship, a single speed-selecting element for,controllingsaid variable speed devices, said element being operatively connected toadjust one of said variable speed devices directly, and meansinteroper'ative with a speed-selecting movement of said element topre-select an adjustment for another of said variable speed devices andto cause slow rotation of said first variable speed device 41. In amachine tool, 21 speed changing tramsmission mechanism including a.plurality of variable speed devices arranged in series relationship,anda single speed-selecting element movvariable speed devices arranged inseries rela-' -tionship, a clutch disposed to actuate said transmissionmechanism selectively, a brake engageable to stop said ,transmissionmechanism, a single speed-selecting element disposedto control saidvariable speed devices and functioning directly to adjustoneofthem,meansinteroperative with movement of said speed-selectingelement to disengage said clutch and said brake and to 15 pre-select anadjustment for another of said variable speed devices while causing slowrota- ,tion of said transmission mechanism during adjustment of saidfirst variable speed device,

and means operative subsequent to movement of said speed-selectingelement to efi'ect the preselected adjustment of said variable speeddevice and to engage said brake.

13. In a speed changing transmission and control mechanism for a machinetool, a plurality of variablespeed devices arranged in series relationship, a speed selecting element operative to adjust one of saidvariable speed devices directly and to pre-select an adjustment foranother of said variable speed devices, and means interoperative with aspeed-selecting movement of said selecting element to turn saidtransmission mechanism slowly for facilitating, adjustment thereof.

44. In a speed changing transmission and con- 35 trol mechanism for amachine tool, a plurality of variable speed devices arranged in seriesrelationship, poweractuated means disposed to addjust one of saidvariable speed devices, and a single speed-selecting element operativeto effect direct adjustment of another, of said variable speed devicesand to control said power actuated adjusting means, the arrangementbeing such that should said power actuated variable speed device resistadjustment, said speed-selecting element may be moved to complete theadjustment of said other variable speed device without interference.

45. In a speed changing transmission and control mechanism for a machinetool, the combination with a manually actuated speed changing device anda, power actuated speed changing device, of a manually actuatedspeed-selecting element operative upon speed-selecting movement toadjust said manually actuated speed changing device directly and topre-select an adjustment for said-power actuated speed changing device,

and means operative to energize said power actuated speed changingdevice for adjusting it in accordance with the adjustment thereofpre-selected by said speed-selecting element.

. 46; In a machine tool having an adjustable rate changing powertransmission mechanism, the combination with main driving meansselectively engageable to. drive said mechanism at normal operatingspeed, of an auxiliary slow speed driving means engageable automaticallyupon disengagement of said main driving means and operative as to braketo reduce the speed of said transmission mechanism quickly to a low rateadapted to facilitate adjustment of said mechanism: i

47. In a machine tool, the combination with a 4 power transmissionmechanism comprising serially arranged shiftable rate change devices andclutch means operative'to interrupt said transmission mechanism, offluid operable means for adjusting said clutch means and for shiftingone of said rate change devices, a rate selector including a chart andan indicator movable relative to said chart, a source of pressure fluidfor operating said fluid operable means, valve means operable to alterthe connection of said pressure source and fluid operable means in,manner to shift said rate change device in accordance with the relativeposition of said chart and indicator means, and other control meansoperative prerequisite to relative movement of said chart and indicatormeans to alter the connection of said pressure source and fluid operablemeans to shift said clutch to interrupting position.

48. In a machine tool transmissionmechanism including a plurality ofrate changing devices arranged in series relationship, a power operabledevice disposed to actuate one of said rate changing devices, a rateselector device disposed to actuate directly another of said ratechanging devices and including a chart having markings indicatingvarious rates corresponding to difierent settings of said rate changingdevices, and control apparatus operable by said rate selector andfunctioning to control said power operable device in manner to effectcombined settings of said rate changing devices in accordance with theindications of said chart.

JOSEPH B. ARMITAGE.

